1. Field of the Invention
The present invention relates to a gas sensor.
2. Description of the Related Art
Hitherto, there have been known gas sensors for detecting the concentration of a predetermined substance, such as NOx, in measured gas such as an automobile exhaust gas. For example, Japanese Unexamined Patent Application Publication No. 09-196885 describes a gas sensor including a sensor element which is placed in a tubular body made of metal and which detects the concentration of gas at the tip of the tubular body, a connector in contact with an electrode placed on the back end side of the sensor element, an elastic body (grommet) attached to a back open end of the tubular body, and a lead which is connected to the connector and which extends outward from an open end of the tubular body through a through-hole of the elastic body. In the gas sensor, two sites spaced at a predetermined distance in an axial direction of the tubular body are swaged, whereby the elastic body is fixed to the tubular body by multi-stage (two-stage) swaging.